The present invention relates to a communication system for aircraft and in particular to a system for transmitting electronic data between an aircraft and a terrestrial base station.
The invention has been developed primarily for use with passenger aircraft and will be described hereinafter with reference to that application. However, it will be appreciated that the invention is not limited to that particular field of use.
In recent times, portable computers such as xe2x80x9claptopxe2x80x9d PCs and devices such as the Apple(copyright) Newton or other palm-held devices (PDAs) running Microsoft(copyright) Windows CE, for example, have become available. There have been commensurate improvements in mobile or cellular telephone technology and in protocols for transmitting computer-generated data across cellular networks. By employing a PCMCIA modem, for example, which allows data to be transferred between the laptop or PDA and mobile telephone, these twin developments have allowed e-mail messages and other electronic data to be sent and received by an individual at one of many locations, without the need to connect via a fixed land telephone line.
Several communications networks for providing telecommunications to airborne users are also known. For example, the North American Telephone System (NATS), including providers such as ATandT and Airfone, have installed terminals in many commercial aircraft to allow passengers to connect a laptop or PDA and transfer data from the passenger""s seat.
In addition to terrestrial based aeronautical communications, satellite service providers such as Inmarsat provide airborne passengers communications from virtually any global location. Similar services are also offered by Iridium, who has launched another network of satellites. Furthermore, other satellite providers have or are launching constellations of satellites with the intention of providing airborne passenger communications.
One serious drawback of existing aeronautical passenger communications is the expense. In most cases, the passenger connects the laptop or PDA to a seat mounted handset using an integrated RJ11 jack. The passenger must make a modem connection to their ground based access server, provide authentication information, and then retrieve or send data. This process is generally technically challenging and unreliable. Even for the transfer of small amounts of data, one or more calls of one or more minutes is necessary. Furthermore, the existing speed of transmission, defined as bits per second (bps), is relatively slowxe2x80x94for example, the INMARSAT satellite services currently limit the data rate for passenger modem communications to 2400 bps. Thus, the time taken to transfer large amounts of electronic data, and the consequent expense, can become prohibitive.
In addition, the reliability of connection when employing a wireless link has been perceived as a major drawback during transmission of data in this way.
Thus, until now, the use of portable computers on aircraft, for sending and receiving electronic mail and browsing World Wide Web (WWW) sites has not been deemed feasible.
It is an object of the present invention to overcome or substantially ameliorate one or more of the disadvantages of the prior art, or at least to provide a useful alternative.
According to a first aspect of the invention there is provided a system for transmitting electronic data between a computer terminal on an aircraft and a terrestrial base station, the system including:
a server mounted upon or within the aircraft for communicating with the computer terminal wherein the terminal is disposed remotely from the server; and
a terrestrial base station for selectively communicating with the server to allow the data to be passed between the base station and the terminal.
Preferably, the base station communicates with the server via a link selected from one or a combination of: one or more wireless links; and one or more wire links. More preferably, the base station communicates with the server via one or more wireless links, each of those wireless links being selected from the group comprising: a satellite link; a cellular telephone link; a microwave link; a NATS compatible link; and another communication system. Even more preferably, the selection of the or each link is dependent upon one or more of: the availability of each link; the relative cost of each link; and the relative speed of each link.
Preferably also, the system includes a plurality of spaced apart terrestrial base stations and the server communicates selectively with one or more of the stations. More preferably, the base station with which the server selectively communicates is dependent upon the position of the aircraft with respect to the stations.
In a preferred form, the server communicates with a plurality of remotely disposed computer terminals located on the aircraft for allowing communication of the electronic data between the base station and the respective terminals.
Preferably, the terrestrial base station selectively communicates with an Internet service provider (ISP) or corporate mail server to collect the electronic data and provide it to the terminal via the server.
More preferably, the data is communicated between the server and the terminal using one or more of: SMTP; HTTP; POP3; or IMAP. More preferably, the data is collected from the ISP or corporate mail server and delivered to the base station using POP3 or IMAP.
More preferably, the base station is able to communicate with a corporate mail server that is behind a firewall. The corporate subscriber can provide firewall static user id and password once when signing up for service, arrange for VPN 150 to have secure access behind the corporate firewall, or the corporate subscriber can provide dynamic user id and password information the first time requesting e-mail retrieval.
In a preferred form, the base station includes means for providing a first signal indicative of the structure of the data and the terminal includes means for generating a second signal in response to the first signal confirming that the data is to be transmitted to the terminal. More preferably the first signal is indicative of one or more of the following: text; file type; attachments; graphics; backgrounds; and the like. Even more preferably, the second signal confirms to the base station which portions of the data are to be transmitted.
Preferably, the base station stores electronic data to be transmitted from the base station to the server, and the server stores electronic data to be transmitted from the server to the base station, the server and base station communicating with each other intermittently.
In a preferred form, the server includes a database of information, the database being updated periodically by transmission of electronic data from the base station to the server. More preferably, the server allows the terminals to access the database. Even more preferably, the terminals access the database with a web browser.
Preferably also, the server communicates with that base station which is nearest to the aircraft. More preferably, the server determines which of the base stations is nearest by determining the current location of the aircraft. More preferably, the server communicates with one only of the base stations. Alternatively, the server communicates with selectively with more than one of the base stations, the selection being made on the basis of the available remaining capacity of the respective base stations.
Preferably, the server communicates selectively with one of the base stations, the selection being made on the basis of the least expensive communication route that is made available by the respective base stations.
In a preferred form the computer terminal is suitable for either browsing the Internet or sending and retrieving e-mail. More preferably, the terminal is a portable personal computer. However, it is also preferred that the terminal is a PDA, or a fixed terminal installed as a part of the aircraft, for example as a part of the in-flight entertainment system.
According to a second aspect of the invention there is provided a method for transmitting electronic data between a computer terminal on an aircraft and a terrestrial base station, the method including the steps of:
providing a server mounted upon or within the aircraft for communicating with the computer terminal wherein the terminal is disposed remotely from the server; and
selectively communicating between a terrestrial base station and the server to allow the data to be passed between the base station and the terminal.
According to a third aspect of the invention there is provided an aircraft computer communication system including:
a first port and a second port located on the aircraft for allowing the establishment of a first network node and a second network node respectively; and
a network located on the aircraft for linking the first node and the second node and allowing communication between the first node and the second node.
Preferably, the network includes a telephone system and the second node is connected to the telephone system. More preferably, the second node is connected to the telephone system with a modem connection. Even more preferably, the first node is connected to the telephone system with a CEPT-E1 connection. In a further preferred form the CEPT-E1 connection complies with an ARINC 746, attachment 11 radio bearer system interface.
Preferably also, the first and the second network nodes are a server and a computer terminal respectively.
According to a fourth aspect of the invention there is provided an aircraft computer network including:
a network hub located on an aircraft for allowing the transfer of first electronic data from the network to a base station;
a first port and a second port located on the aircraft for allowing the establishment of a first network node and a second network node respectively, wherein the nodes transfer respective second and third electronic data to the network via the hub such that the first data includes selected portions of the second data.
Preferably, the second data includes selected portions of the third data.
According to an fifth aspect of the invention there is provided a method of communicating between a first node and a second node of an aircraft computer network, the method including the steps of:
locating a network hub on an aircraft for allowing the transfer of first electronic data from the network to a base station;
locating a first port and a second port on the aircraft for allowing the establishment of the first network node and the second network node respectively, wherein the nodes transfer respective second and third electronic data to the network via the hub such that the first data includes selected portions of the second data.
Preferably, the second data includes selected portions of the third data.
According to another aspect of the invention there is provided a method of communicating between a first node and a second node of an aircraft computer network, the method including the steps of:
locating a network hub on an aircraft for allowing the transfer of first electronic data from a base station to the network;
locating a first port and a second port on the aircraft for allowing the establishment of a first network node and a second network node respectively, wherein the network transfer respective second and third electronic data to the nodes via the hub such that the second data includes selected portions of the first data.
Preferably, the third data includes selected portions of the second data.
In the preferred embodiment each base station is capable to connecting to the Internet, and able to communicate with various Internet service providers and computing resources throughout the world. Thus, rather than each passenger on the aircraft connecting individually via a satellite link, for example, to an Internet service provider, the passengers all connect to a central server on board the aircraft. This airborne server then establishes a connection a base station as necessary. Thus, the efficiency of data transmission between a passenger and their normal ISP may be improved, and the overall cost of transmission to and from the aircraft may be significantly reduced. Further efficiency is gained by using compression software to reduce the quantity of data (bits) that needs to be sent between the airborne server and a base station. A radius client interface is provided by the server/base station to interact with Radius servers for end user authentication and network access requests.
In one configuration, the server and the base station can store and forward requests; for example by a passenger to retrieve e-mail from their ISP/corporate mail server. This may require the passenger""s laptop to be connected for the duration of the data exchange between the airborne server and a base station, which can be restricted to 2400 bps or less. Furthermore, there may be no means to restrict or control the flow, for example, of very large attachments.
In another configuration, the server and base station can provide a proxy service, whereby, for example, the base station can retrieve e-mail on behalf of the passenger, including behind a corporate firewall, and transmit this information to the airborne server, and the airborne server can transmit passenger provided e-mail to the base station, in both cases, without the passenger""s laptop being connected to the aircraft network. The airborne server collects the e-mail and provides it to the passenger on demand. The aircraft network data rate is not necessarily restricted by the data rate of communications between the airborne server and a base station.
The aircraft network may be comprised of a dedicated cables and circuitry between the server and dedicated ports in the seat. Alternatively, the aircraft network may be wholly comprised within an existing aircraft system, such as the airborne telephone system.
The system of the preferred embodiment thus provides for e-mail transmission and reception, for example, for a larger number of users, each having different Internet Service Providers or corporate e-mail accounts, which may in turn be in different countries.
The protocol used for sending data from the or each remote computer terminal to the server, and from the server to the or each remote computer terminal, is preferably TCP/UDP. Protocols supported by this connection include FTP, SMTP, HyperText Transfer Protocol (HTTP), POP3, IMAP and DNS.
Preferably also, any data to be sent from the base station to the server is first analyzed to determine its structure (unlike store and forward principals). Most preferably, the base station sends to the server structure data indicative of the structure, the structure data being then communicated to a predetermined one of the remote computer terminals. This technique prevents large attachments, for example, to e-mail messages from being sent across the relatively low bandwidth link between the base station and the server, other than where the relevant passenger agrees to pay a nominated fee. That is, upon being informed of the data structure, the user of the remote terminal within the aircraft is provided with the choice as to whether the attachment need be obtained. The passenger can interact with the server through the use of server generated web pages.
Preferably, the base station is arranged to store electronic data to be transmitted from the base station to the server, and the server is arranged to store electronic data to be transmitted from the server to the base station, the server and base station communicating with each other intermittently.
To minimize cost and improve efficiency, the server and base station preferably each store electronic data as they receive it from the individual users on the plane and their Internet service providers/corporate accounts respectively. In one embodiment, a connection is then made intermittently. During each connection, data is exchanged between the server and base station, and after exchange has been completed, the connection is terminated. For example, in one embodiment the server and base station exchange data for one minute or so, every fifteen minutes. Compression software is used to minimize data transfer.
In one preferred form the system includes a plurality of base stations. For example, each Continent may have a separate base station. The server preferably connects with that base station which it is nearest to at a given time. In other embodiments, however, a single base station is utilized.
The server also preferably acts as a virtual WWW. For example, in one embodiment the server stores a plurality of pages of information from a number of web sites. Because this information is stored on board the aircraft, it may be accessed very rapidly and without significant communications expense. The server redirects the passenger browser to appropriate web pages available locally.
The external link, however, allows updating of the stored pages from time to time. Most preferably, the web pages are stored in a cache which is updateable differentially. That is, as changes to a particular web page are effected, only the new or amended parts of each page need be sent via the wireless link, rather than the full page.
Preferably, the server includes a mass storage device which is updated to the latest available content prior to departure of the aircraft from a port of call.
Preferably also, the passenger establishes a PPP connection between the remote computer terminal and the server, normally using a specially provided dialer application. In other embodiments, however, the dialer application is manually configured. Even more preferably, the server captures the passenger user identification and password to be used by a Radius client for user authentication against a Radius server and if applicable a corporate firewall.
The base station preferably receives authentication from a Radius server, delivering e-mail from the passenger and retrieving the passengers e-mail from the passengers Mail server. More preferably, the base station provides the passenger e-mail to the server, with indications of any additional attachments and the base station provides any passenger instant messaging, which will be delivered to the passenger""s terminal and displayed using a resident application, such as the dialer. Even more preferably, the server provides the e-mail to the passenger e-mail client with the passenger subsequently retrieves e-mail. Further preferments include interacting the passenger and the server to determine if any additional attachments should be retrieved and, if so, retrieving the attachments from the base station.
Preferably, the passenger browses the world wide web content provided by the server.
In a preferred form, the server/base station use Simple Network Management Protocol (SNMP) for network monitoring.
Preferably also, the server and base station maintain accounting of all transactions for billing purposes. Preferably also, the server and base station monitor passenger activities and recording these activities for other uses. More preferably the server and base station determine when to cease retrieving e-mail on behalf of the passenger and when to delete e-mail messages that have been delivered to the passenger computer terminal within the passenger e-mail mail server if required.
It will be understood that preferred features of this method may correspond to the preferred features of the system of the present invention.
Unless the context clearly requires otherwise, throughout the description and the claims, the words xe2x80x98comprisexe2x80x99, xe2x80x98comprisingxe2x80x99, and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of xe2x80x9cincluding, but not limited to.xe2x80x9d